Connecting means for electrical switches



Feb. 23, 1932; A. M. PHELAN I CONNECTING MEANS FOR ELECTRICAL SWITCHES Original Filed Aug. 12. 1927 Ell/[III] [If/III 555555,. @UULJLJLJQLJ Patented Feli. 23.,1 932 UNITED STATES .P'ATENT OFFICE- LOUIS A. I. PHELAN, OF ASBIG'NOB, BY HESNE ASSIGNMENTS, TO MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS, MINNESOTA,

A CORPORATION 01' DELAWARE comc'rmc Mamas ron' anncmnrcn. swrrcinzs Application filed August 12, 1927, Serial No. 212,365. Renewed July 9, 1931.

This invention relates to electrical switches and has special reference to a means for connecting the actuating means and the switching means of an electrical switch.

More particularly, this invention relates to a frictional connection between the actuating means and the switching means whereby when the switching means has been actuated to ef- ;fect a change of circuit connections, the actuating means may continue to operate without further moving the switch. Moreover,

when the actuating means changes its direction of movement to return to its original position, the switching meansshall immediatefor use in electrical circuits where a minimum of electrical energy is procurable. Qne well known type of such an electrical switch a tiltable switch which is actuated by a the-rmostatic element. The switching means as usually provided in a tiltable switch com- 1 sov prises a mercury contactor tube and is actuated by a very slight tilt or over the center movement to efiect a change of circuit connec; tion. By reason of the tiltable switch requiring but a minimum ofenergy for actuating purposes, these switches are very delicate in structure and in general characteristics and a great difliculty has existed in finding means or permitting the actuating member to over- I ride or continue to move in the samedirection after the switching means or the contactor tube has reached a predetermined limit to effeet a change of circuit connection. An example may be obtained b referring to a heating system wherein a r the electrical circuit controlling the heating system hasbeen opened, the temperature continues to rise for a substantial period thereafter. How- I ever, in such a system, it is desirable that the temperature be maintained within the limits of two or three degrees of temperature,.and therefore, the actuating element should not be permitted to actuate the tiltable switch into such a distant position aswvoul-d require a temperature change of several degrees for it to return to a closedcircuit position.

this same illustration, it is further desirable that the. electrical switch be returned to itsoriginal position toclose the electrical circuit controlling the heating system upon a very slight tilt or over the center movement of the contactor tube. Therefore, it is one of the objects of this invention to provide that the switch shall be immediately actuated upon the changing in direction of the actuating element. n

One specific application of this present in-' by means of anoverload in the electrical cir-- cuit'or by anyother means. However, the application of the frictional connecting means of the present invention will now be specifically recited in connection with what is well known as a stack switch.

For a better understanding of the characteristic features of this invention, reference may now be had to the following description and the accompanying drawings in which drawings: h

Figure 1 is a front elevational view of an electrical switch mechanism embodying this invention showing the cover removed from the face of the casing enclosing the same;

Fig. 2 is a vertical sectional view taken on the line 2- Z of Fig. 1; and 1 Fi 3 is an enlarged detail view of the frictional means for connecting the actuatinglmeansand the switching means. i eferring now more particularly to the drawings, the electrical switch comprises a casing 10 having a cover-11 secured thereto in anydesirable manner. The'rear surface of the bearing member is provided with a projecting member 12, which either may be cast integrally therewith or ma be'formed in a separate pie'cie. A short tu 13 is disposed on the projecting member 12 and -is held in position therewith by means of a 'stantially centrally through the helical bi-.

metallic element 16, tube 13 and into the casing 10. The rod is journalled in a suitable aperture formed in the projecting member 12. When a combustion is obtained in the furnace or boiler, the heat therefrom rises in the stack to'contact with the bimetallic element to cause the latter to expand to rotate the rod 17. Upon the lack of combustion in the furnace or boiler, and a consequent cooling of the stack, the bimetallic element is caused to contract, thereby changing its direction of movement to rotate the rod in the opposite direction.

An arm 18 is loosely mounted on-the end of the rod 17 within the casing 10 and carries a mercury tube contactor 'switch19. An

insulating block 20 is mounted on suitable supporting brackets and has a plurality of binding posts 21 positioned thereon for receiving the lead wires 22 leading from the contactor switch 19. r

The mercury tube contactor 19 is of the usual type comprising a hermetically sealed glass container having cooperative spaced electrodes disposed therein and a quantity of current conducting fluid such as mercury for bridging the electrodes when the container is tilted in one direction. Conversely, when the container is tilted in the opposite direction, the mercury in the tube flows away from i the electrodes. The electrodes are connected to the lead wires 22, which latter are connected to the binding posts 21, the binding posts, in turn, being connected to the device or system to be controlled. 0

The arm 18 is an elongated member preferably stamped from a sheet of metal and extends a substantial distance on each side of the rod 17. A locking means as, for example, a pair of lock nuts 23 are mountedon the threaded end portion of the rods 17 The arm 18 is disposed between two cup shapedwasher members 24, one of said washers abutting the lock nuts 23. A nut 24 is disposed on the outermost end portion of the rod 17 'and' in threaded engagement therewith and likewise has a cup sha d washer 25 adjacent thereof for positionmg a coil spring 26 around therod 17, the ends of the coil spring bearing against the, cup-shaped members 24 and 25. It'will be apparent that the coil spring 26 rovides a tension on the arm 18 whereby t e latter has a frictional engagement with therod 17 The amount of tension of the spring 26 is determined by an adjustment of the nut 24. I

A pair of stop or limiting members 27 are.

mounted on the casing 10, thesemembers being pins of a suitable length. In order to permit of an adjustability between the two pin members, a plurality of apertures are disposed in the rear wall of the casing and the proper aperture is selected to receive the pin. The upper end of the arm 18 is received between the stop or limiting members 27 to limit the distance through which the contactor 19 may be tilted when actuated by the bimetallic element 16.

In the operation of the device, the rod 17 obtains a rotary movement from the actuat- .ing' element 16 as before described and this rotation is imparted to the arm 18 by reason of the frictional engagement between the spring 26 bearing against the arm and the locking members 23. When the upper end of the arm 18 contacts with one of the stop members 27, the movement of the arm 18 is arrested. However, the actuating element may continue to move and to rotate the rod 17 since there is but a frictional engagement between the arm 18 and the rod 17. However, immediately upon a reversal of direction of rotation of the actuating element 16, the arm 18 will be icked up and move in a reverse direction, 1t not being necessary to await the return of the actuating element to the point at which the contact was previously arrested.

As a result of this invention, the frictional mounting insures that upon a reversal of direction of rotation of the helical bimetallic element 16 and the rod 17 and immediate a means for engaging the stop members. The

remaining elements of the frictional means are simple stampings and standard parts which are easily manufactured and readily assembled. Further, the contactor 19 is mounted in aclip which latter is fixed to the arm18 by means of a simple eyelet which also reduces the cost of construction and assembly to a minimum.

While but a single embodiment of thisinvention is herein described I desire that the same be limited only by the scope of the ap pended claims and the prior art.

I claim: Y 1. In a device of the class described, a

casing, a tiltable switch housed therein, coiled actuating means for said switch that projects laterall from said casing and being free to move without restraint, means for adjustably predetermining the limits of movement of said switch, an arm also housed in said casing actuated by said actuating means for carrying said tiltable switch and extending to engage said adjustable limiting means, and an accessible adjustable spring member for frictionally engaging said actuating means and said arm.

2. In a device of the class described, a

said second abutment and said arm to. effect a frictional connection between said thermostatic means and said tiltable switch.

3. In a device of the character described, a casing, switching means housed in said casing, said casing having a plurality of spaced apertures on a wall thereof, a pair of pins for engaging any two of said apertures, coiled heat responsive actuating means for said switch extending exteriorly from said casing, carrying means frictionally held on said actuating means operating between and limited by said pins whereby said actuating means may have an overriding movement without being subject to restraint at the limit of movement of said switching means but insuring an immediate reverse movement of said switching means upon a reverse movement of said actuating means.

4. An electric switch comprising a casing, an actuator extending exteriorly of said casing and adapted to move without restraint through a relatively wide range, a mercury electric contactor housed in said casing, a holder therefor, said holder adapted to move through a relatively narrow range, means for adjusting the span of the range through which said holder moves, and yielding continuously acting frictional slip connecting means between said holder and said actuator whereby relative movement therebetween obtains when said holder reaches either end of its narrower range of movement and without imposing restraint on said actuator.

5. An electric switch comprising a casing, an actuator extending exteriorly of said'casingand adapted to move without restraint through a relatively wide range, a mercury electric contactor housed in said casing, a holder therefor, said holder adapted to move through a-relatively narrow range, means for adjusting the span of the range through which saidi holder moves, yielding continuously acting frictional slip connecting means between said holder and said actuator whereby relative movement therebetween obtains when said holder reaches either end of its narrower range of movement and without imposing restraint on said actuator, and means for adjusting said yielding continuously acting frictional slip connecting means. 7

6. An electric switch comprising a casing, a coiled heat responsive actuator extending exteriorly from said casing and adapted to move without restraint through a relatively wide range, a mercury electric contactor housed in said casing, a holder therefor, said holder adapted to move through a relatively narrow range, means for adjusting the range of movement of said holder, and yielding continuously acting frictional slip connect- -ing means between said holder and said actuator whereby relative movement therebetween obtains when said holder reaches either end of its narrower range of movement without imposing restraint upon said actuator.

7 An electric switch comprising a casing, a helically coiled heat responsive actuator extending exteriorly from said casing and adapted to move without restraint through a relatively wide range of movement, an electric switch housed in said casing and controlled by said actuator, said electric switch being adapted to move through a relatively narrow range for the purpose of opening and closing an associated electric circuit, means for adjusting the span of the range through which said electric switch may move, and yielding continuously acting frictional slip connecting means between said electric switch and said actuator whereby relative movement therebetween obtains when said electric switch reaches either end "of its narrower range of movement without electric, switch and said actuator whereby relative movement therebetween obtains when said electric switch reaches either end of its narrower range of movement and without imposing restraint on said actuator.

9. An electric switch comprising a casing, a coiled heat responsive actuator'exteriorly thereof and adapted to move without restraint through a relatively wide range, an electric switch housed in said casing and controlled thereby which is adapted to move withina range limited in at least one direction, means for adjusting the range through which said electric switch may move, -'frictional slip connecting means between said actuator and said electric switch whereby relative movement therebetween obtains after said electric switch has moved in at least one direction to the limit of its range, and without imposing restraint on said actuator, and means for adjusting said frictional slip connecting means.

10. An electric switch comprising a casing, a coiled thermal element extending laterally therefrom and having one end fixed and the other end movable without restraint, a rotatably mounted holder in said casing and adapted to be moved by said movable end of the thermal element, a mercury electric eontactor mounted on said holder, adjustable means for limiting the degree of movement of said holder, and frictional slip connecting means interposed between said holder and said movable endof the thermal element, said connecting means comprising an adjustable spring element.

11. An electric switch comprising a casing, a coiled thermal element exteriorlythereof and having one end fixed and the other end movable without restraint, a r0- tatably mounted holder within said casing and adapted to be moved by said movable end of the thermal element without imposing restraint thereupon, a mercury electric contactor mounted on said holder, adjustable means for limiting the degree of movement of said holder within the span of movement of said movable end of said thermal element, and slip connecting means interposed between said holder and said movable end of the thermal element, said connecting means comprising an adjustable spring element.

In witness whereof I have hereunto subscribed my name.

LOUIS A. M. PHELAN. 

